The invention relates to a drilling machine for a drilling rig and to a drilling rig which can be used for exploratory drillings and producing wells, particularly in hydrocarbon deposits, both onshore and offshore, and to a method for sinking such a well.
Modern drilling rigs according to the prior art consist of a large number of components, such as a drawworks, an iron roughneck, a working stage, a pipe-handling apparatus, a pipe rack, a crown block with a traveling block and a top drive, a pipe ramp and a catwalk for the drilling pipe, together with various auxiliary devices for handling.
Such drilling rigs have the disadvantage that they consist of a large number of components which, because of the constant changing of the drilling location of the drilling rigs, entail elaborate and costly logistics and large numbers of personnel.
European published patent application 0 243 210 A2 describes, for example, a conventional drilling machine of modular construction. It contains all components necessary for drilling machines, such as a collapsible drilling tower, which rests on a displaceable substructure by means of four legs. In its upper part it has a crown block and a top drive, together with a traveling block, and in its lower part it has a breaking and securing apparatus. Part of the drilling mast is directed by means of lifting cylinders. The absolutely necessary drawworks is arranged on the displaceable substructure and, via cables and via the crown block, forms a connection to the top drive. In addition, a pivotable pipe handling boom is provided which guides the pipe into the drilling machine.
However, this drilling machine still has a large number of components which, although of modular design, nevertheless have to be assembled and dismantled and transported from drilling location to drilling location. This requires a substantial effort in terms of personnel and logistics.
It is an object of the present invention to provide a drilling machine and a drilling rig, and also a method entailing substantial savings with regard to the equipment of the drilling rig and with regard to logistics and personnel costs.
The drilling machine according to the invention consists of a base, on or in which a top drive displaceable axially to the longitudinal axis of the base and a pipe-handling apparatus which is movable, especially by sliding, perpendicularly to the longitudinal axis of the base and which grips the drilling pipe, are arranged, the base being pivotably and/or rotatably mounted in the region of the foot.
The bearing of the foot of the base may be mounted on or below the working stage of a drilling rig in the region of the drilling cellar or on a vehicle, such as, for example, a mobile workover rig. The ground, in other words the surface of the terrain, may also be used as a working stage. With a drilling machine of this type, the main drive and handling components are advantageously integrated in one system. This also eliminates the crown bearing, traveling block and drawworks that are customary in drilling rigs according to the prior art. Similarly, the pipe ramp and the catwalk are omitted. In addition, this integrated construction allows rapid transport from one drilling location to another (rig move time) and a reduction in the numbers of drilling personnel required. It is even possible to raise and set down the drilling machine according to the invention using a dirigible with a maximum lifting power of 160 tons, as this drilling machine is much lighter than a comparable drilling machine according to the prior art. Preferably, the base is formed in a type of rocker, for example in the form of a box structure.
A further embodiment envisages that a power roughneck is arranged below the pipe-handling apparatus and comprises a holder and a breaking and securing apparatus, the holder customarily being arranged below the breaking and securing apparatus. It is particularly advantageous to arrange only the breaking and securing apparatus in or on the base and to provide the holder, for example, on or under the working stage in order thus to reduce the weight of the base. The roughneck may also be arranged on the working stage.
In a further embodiment, the drilling machine may be designed to be horizontally slidable. This has the advantage that a drilling machine, especially an erect drilling machine, can be moved out of the region of the well and, in addition, adjusted relative to any pipe stores or to the center line. In addition, pipes can advantageously be removed from a plurality of pipe stores arranged side by side.
A locking apparatus is arranged at the upper end of the base and is connected to a steel structure, preferably a tower or a mast. This has the advantage that an additional rigidity for connection or bending purposes is achieved, and the steel structure can be much more simply and flexibly constructed than customary towers or masts. A further embodiment envisages that the locking device consists of a hollow cylinder to which a flushing hose is connected and on which a valve is arranged to ensure the flushing feed. Specifically when the base is pivoted, it is advantageous to integrate the flushing feed into the locking device, so that flushing is available virtually automatically without a further working step.
A drum may be arranged on or in the base, onto which the flushing hose can be rolled up, so that the risk of fracture or other damage during the laying and removal of pipes is avoided.
An elevator is provided for raising the base from the horizontal to the vertical, which, in a particularly advantageous embodiment, consists of one or more hydraulic or pneumatic cylinders or, in another alternative embodiment, is designed as a winch. As a result, drilling at an angle of from 5xc2x0 to 90xc2x0 to the surface of the terrain is advantageously enabled.
The top drive of the base can be designed to be displaceable by means of a linear drive, the linear drive being arranged in or on the base. Examples of linear drives that may be used include a spindle drive, a hydraulic drive and a chain or cable hoist. Guidance can be ensured, for example, by a sliding rail, racks or guide rollers. The linear apparatus consists of drive and guide means.
This has the advantage that workover, drilling and snubbing operations (e.g. pipe laying) can be carried out.
In a further embodiment, a pipe rack is arranged within the range of the pipe-handling apparatus, the individual pipes being arranged standing in the pipe rack. This has the advantage that the base can engage independently on the pipes, without additional apparatus, and then lower them into the well by means of the top drive.
The pipe-handling apparatus as a whole or the grippers or the gripper seating are arranged to be displaceable axially to the longitudinal axis of the base, which advantageously makes it possible to handle the pipes more efficiently as, for example, when setting down the pipe or removing it from the pipe rack. A further advantage lies in the fact that, by means of such a pipe-handling apparatus, the plug and socket thread of the pipe connector can be pushed together within a permitted travel.
A further advantageous embodiment envisages that the steel structure has a working stage, the fulcrum and/or pivot point of the base being arranged above or below the working stage.
As a result of the many possible variations of the drilling machine, it becomes possible to adapt the drilling machine to local conditions at the drilling location.
A further advantageous embodiment envisages that a damping device is arranged on the base and/or the steel structure, which prevents damage being caused by uncontrolled impact when erecting the base or when locking. Thus, advantageously, damping of the load when erecting or laying down the base can be achieved.
A line for flushing is provided on or in the base, the lower connector of the line being connected to the flushing pump and the upper connector being connected via the hollow cylinder to the flushing hose. This advantageously permits the integration of an additional unit, specifically the flushing supply for the well, into the base.
In one particular embodiment, the roughneck is pivotably connected to the base by means of a hinge, which is arranged on one side of the roughneck, or, in a different embodiment, is connected to the base in such a manner that it is displaceable perpendicularly to the axis of the base. A further possibility is for the roughneck to be raised via a coupling by means of the top drive. The advantage of such an embodiment lies in the fact that the down hole equipment can be installed in the well even with the base standing vertical. The hinge may be designed, for example, as a welded hinge. The roughneck may also be mounted on the working stage in a conventional manner.
In a further embodiment of the drilling machine part of the steel structure, preferably one or more corner pillars of the steel structure, is designed as a pipe rack or as a seating for a pipe holder. This saves weight, and simplifies the device as a whole, as fewer components are needed which, overall, permits both a cost saving and the establishment of a modular system. In this embodiment, the pipe rack or seating for a pipe holder can also be mounted to rotate about its longitudinal axis. The advantageous result of this is that the loading of the magazine can take place irrespective of continuing drilling operation, and that one pipe is always located within the gripping range of the pipe-handling apparatus for removal. Also particularly advantageous is an embodiment which envisages that the drilling machine and/or the pipe rack is mounted on a vehicle or a trailer, thus significantly increasing the portability and also the flexibility of use.
The invention also covers a drilling rig having two or more drilling machines are arranged and are alternatingly moved or rotated or pivoted over the center of the well. The advantageous effect of this is that drilling times can be substantially reduced, because one drilling machine can be loaded while another drilling machine is still sinking the well. Since the loading drilling machine is not located above the well during the loading operation, the second drilling machine is able to connect the previously loaded pipe with the pipe string in the well and continue sinking the well. A further advantageous effect of this is the creation of a drilling rig which can be used for virtually continuous drilling. Also, only a minimum of drilling personnel are required, since the drilling rig according to the invention can be run almost fully automatically, particularly in the handling of the pipes, casings, etc. Drilling machines which are rotatably mounted need not be connected and can be separately driven.
A particular embodiment of such a drilling rig envisages that two drilling machines are arranged substantially symmetrically, especially with axial symmetry, to the center line, the drilling machines being connected to one another. This connection is preferably performed by a substantially kinematic chain, a claw shaft, a cable or a chain. As a result, advantageously, it is possible to reduce the energy output for setting down a pivotable drilling machine while simultaneously erecting another drilling machine, both axes of the drilling machines extending in parallel. Drilling machines which are rotatably mounted need not be connected and can be separately driven.
These advantages can also be achieved if a steel structure is arranged between two drilling machines, to which steel structure the drilling machines can be reciprocally locked, the drilling machines being connected by means of cable or chain via a return point or a return roller which is arranged in the steel structure.
An embodiment wherein a damping device is arranged on the support devices of the drilling machines or the steel structure, the damping unit for example consisting of a hydraulic cylinder and a choke, has the advantage that the load can be damped when erecting or setting down a base of the drilling machines.
The method according to the invention for sinking a well and for installing drilling pipes is a method wherein a pipe is rolled onto a base of a drilling machine, the top drive being in an upper position, and the grippers of the pipe-handling apparatus are moved into the base, and then the pipe-handling apparatus grips the pipe as soon as the latter is lying in the intended position on the base. Subsequently, the base is raised by means of an elevator from a horizontal position into a position between 5xc2x0 and 90xc2x0, and in a preferred embodiment the base is locked in a steel structure, or in a mast or tower, after the vertical or nearly vertical position has been reached. During the raising of the base or after locking of the base, the top drive is screwed to the pipe by the drive shaft of the top drive and is secured and is then moved with the pipe-handling apparatus or by means of the linear drive into the upper region of the iron roughneck, the lower breaking and securing apparatus of the iron roughneck grasping the lower pipe connector of the pipe and the holder holding the string. The pipe is then screwed by means of the top drive or iron roughneck to the drilling string within the well. The pipe-handling apparatus is again moved into the base and the holder for the lower pipe, connected to the drill bit, is opened and the drilling operation is begun, the top drive being lowered in the guide means of the base. By means of such a method, drilling with an integrated drilling device can be carried out flexibly and quickly with a small drilling crew.
A further stage of the method envisages that the base is displaced horizontally between picking up the pipe and preparing it for drilling and screwing to the lower pipe, which has the advantage that a further drilling device can meanwhile continue sinking the well. A further embodiment of the method according to the invention envisages that the pipe is removed from a pipe rack, in which the drilling pipe is arranged vertically, by means of a pipe-handling apparatus, which is integrated into a drilling device as claimed in claim 1, and the pipe is then screwed to the top drive by means of the pipe connector and brought into the drilling position. The advantage of such a method lies in the fact, that, with the integrated drilling machine, the sinking of the well can take place with economy of space and energy. In a further embodiment of the method, the pipe rack, after removal of a pipe by the pipe-handling apparatus, is rotated sufficiently far about its own longitudinal axis for it to be possible for the next pipe in the pipe rack to be gripped by the pipe-handling apparatus. Thus the next pipe is automatically available for the next drilling section.
The method can advantageously also be embodied in that the drilling machine, after completion of a drilling section and release of the top drive from the drilling string in the well, is rotated about its longitudinal axis and then, after the top drive has been raised, removes a new pipe from the pipe rack by means of the pipe-handling apparatus. Thus the center line becomes free and, while the pipe-handling apparatus of the drilling machine is loading a new pipe, a second drilling machine can continue sinking the well. A further stage of the method envisages that two or more drilling machines are brought into position around a well, one drilling pipe being sunk in alternation while one or more of the other drilling machines are prepared for drilling by receiving a further pipe. As a result of this alternating interplay of two or more drilling machines, a high level of drilling progress per unit time can be achieved and cooling down times can be reduced,
A further embodiment of the method according to the invention envisages that, for the installation of drilling pipes, a pipe is removed from a pipe rack while the pipe rack is simultaneously being charged with further pipes, which has the advantage that the cooling down times can be even more greatly minimized, because the charging of the pipe rack can take place independently of the sinking of the well. This also reduces the drilling down times.
The method according to the invention can of course be employed, by reversing the sequence of method stages, to remove pipes, in which case hoists may also be employed which are arranged below the top drive and independently enclose the pipe (the tool joint). Tractive force is not exerted via the threaded connection as a result.
Instead of pipes, casings, sections, tubing, etc. may be used. The pipe rack may be designed as a pipe bin or finger stage. A pipe frequently consists of a plurality of individual drill rods (double or triple stands), which are screwed together even before being placed in the pipe rack. However, a pipe may also consist of only one drill rod (single stand).
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.